1. Field of the Invention
The present invention is related to methods for reducing and/or preventing microbial contamination in the gastrointestinal tract of animals.
2. Background of the Related Art
The Public Health Service/Centers for Disease Control and Prevention report that each year millions of Americans suffer illness caused by foodborne infection. The Centers for Disease Control and Prevention reported that 79% of outbreaks between 1987 and 1992 were bacterial. More recent data obtained through the CDC-FoodNet indicated that this trend has increased in 1998 to an alarming 94%, or 9,213 out of 9,787 confirmed cases of food derived infection. The reasons for these increases are not clear, though some microbes have demonstrated resistance to standard methods of preparation and storage of foods, not to mention a growing resistance to conventional antibiotics and disinfectants. Additional adverse pressures on the microbial character of fresh and processed foods include changes in agronomic and food processing practices, increased susceptibility of humans to certain pathogens, and the emergence of new virulent strains of bacterial, viral and emerging non-bacterial pathogens. The United States Department of Agriculture estimates that medical costs and productivity losses for 7 specific widespread pathogens in food range between $6.5 billion and $34.9 billion annually. These estimates do not include the total burden placed on society by the chronic illness caused by some foodborne pathogens.
Research in the meat industry has clearly shown that a principle source of pathogen contamination on animal carcasses is the contents of the gastrointestinal (GI) tract (ingesta). Due to the methods and equipment used during the processing of meat animals and poultry, it is impossible to prevent tearing of various constituents of the GI tract and subsequently releasing all or portions of the ingesta onto the fresh meat surfaces. The prevalence of Salmonella and Campylobacter on retail poultry carcasses remains a significant public health concern. Salmonella and Campylobacter together are thought to be responsible for the majority of acute cases of gastroenteritis. E. coli O157:H7 was first recognized as a human pathogen in 1982 when two outbreaks in the United States were associated with consumption of undercooked hamburgers from a fast-food restaurant chain. The pathogen has since emerged as a major cause of bloody and nonbloody diarrhea, causing as many as 20,000 cases of gastroenteritis and 250 deaths per year in the United States. Listeria monocytogenes transmission has been recognized as a major source of human listeriosis since the early 1980s. Listeriosis can cause stillbirths, miscarriages, meningitis, or sepsis in immunocompromised hosts. Case-fatality rates as high as 40% have been reported during outbreaks. Outbreaks have been associated with ready-to-eat foods, including those produced from fresh-processed foods containing meat or animal derived ingredients. This serious food safety problem has led to the development of numerous technologies to address the spreading of animal ingesta onto the meat surfaces during slaughter or the disinfection of the ingesta prior to slaughter.
Current practices in confined animal production include placing the animals through a feed withdrawal period for 4 to 18 hours prior to transportation to the slaughter facility. It is during this feed withdrawal period that poultry begin to peck at the bedding material that, by the time the birds are ready to be shipped to the abattoir, becomes severely contaminated with feces. If these feces contain pathogenic bacteria (i.e., Salmonella or Campylobacter), these organisms will quickly colonize organ lumen areas throughout the digestive tract of the birds, especially in the upper GI tract.
Investigations of poultry processing plants have revealed that the primary digestive organ responsible for harboring most of the harmful upper GI tract bacteria is the crop. During automated evisceration procedures, the contents of the crop are almost always emptied onto processing equipment and/or onto the freshly exposed surface of the bird.
While colonization of the food animal""s gastrointestinal tract may or may not cause disease in the animal itself, removal of GI tract bacterial does decrease the foodborne disease risk associated with consumption of meat and meat byproducts. However, recent data has suggested that colonization of the human GI tract by certain microbes may also lead to significant disease risk. It is estimated that 10% of the people of the US are afflicted by peptic ulcer disease. It is now generally accepted that a significant percentage of peptic ulcers in humans are caused by, or exacerbated by, one or more species of bacteria, including Helicobacter pylori. Additionally, other GI tract diseases thought to be linked to bacteria overpopulation include bowel inflamatory disease and sluggish bowel syndrome.
Therefore, there is a need for a method of controlling the microbial population in the gastrointestinal tract of animals. It would be desirable if the method involved non-invasive, oral administration of a biocidal compound or composition that could be added to drinking water, feed/foodstuffs, or other ingestible forms. It would be even more desirable if the presence of the compound or composition in water or feed/foodstuffs did not effect the consumption of the water or feed/foodstuffs by the animals. It would also be desirable if the compound or composition would decompose or form by-products that are harmless to the animal and, in the case of animals to be slaughtered for consumption, either the byproducts are not partitioned in or on the edible portions of the carcass or are harmless to those consuming the meat of the animal.
The invention is a process for preventing microbial growth in the digestive tract of living vertebrate animals, particularly food animals. Control of microbial growth is achieved by the step of applying a percarboxylic acid or a mixture of percarboxylic acids to an aqueous stream which is subsequently consumed orally by the animal. The formulation can also be mixed into food items or into particulate or similar materials, or packaged in ingestible capsules, whereby the active ingredient enters the body of the animal through the oral cavity through feeding behavior, or food scavenging, or particulate scavenging activities of the animal. Formulations may also be sprayed onto the outside of the animal and taken orally.
The process of the invention is unexpectedly effective in preventing the growth of unwanted microorganisms within body cavities and digestive tract of animals prior to the slaughter of the animal. The formulation exerts its decontaminating effect beyond the oral cavity and into the intestinal regions of the animal. The oral consumption of appropriately formulated percarboxylic acids causes an unexpectedly high level of internal decontamination of the animal.
The process of the invention provides an antimicrobial agent useful in poultry production, such as during the feed withdrawal period that usually extends 0.1 to 1.5 days prior to slaughter. A high degree of internal antimicrobial efficacy is combined with a high degree of palatability by the animal. The formulation can be safely ingested by animals or by humans while imposing no environmental incompatibility or ill health. The consumed percarboxylic formulations break down inside the animals body to harmless end products.
Differentiation of antimicrobial xe2x80x9c-cidalxe2x80x9d or xe2x80x9c-staticxe2x80x9d activity, the definitions which describe the degree of efficacy, and the official laboratory protocols for measuring this efficacy are important considerations for understanding the relevance of antimicrobial agents and compositions. Antimicrobial compositions may effect two kinds of microbial cell damage. The first is a truly lethal, irreversible action resulting in complete microbial cell destruction or incapacitation. The second type of cell damage is reversible, such that if the organism is rendered free of the agent, it can again multiply. The former is termed bacteriocidal and the later, bacteriostatic. A sanitizer and a disinfectant are, by definition, agents which provide antibacterial or bacteriocidal activity. In contrast, a preservative is generally described as an inhibitor or bacteriostatic composition.